Porton Down, UK; 18 July 2011: GW Pharmaceuticals plc (AIM:GWP) today announces the launch in Denmark of Sativex® oromucosal spray as a treatment for the relief of spasticity in Multiple Sclerosis (MS).

Regulatory approval for Sativex® was granted in June 2011 by the health authorities in Denmark.

Sativex® is also approved and marketed in the UK, Spain and Germany. Launch in Sweden is expected before the end of 2011 with additional launches in Italy, Czech Republic and Austria expected in 2012.

Sativex® is also in Phase III clinical development for the treatment of cancer pain. Almirall holds the marketing rights to this medicine in Europe (except the United Kingdom).

Enquiries:

GW PR

GW Pharmaceuticals plc

(Today) + 44 20 7831 3113

Dr Geoffrey Guy, Chairman

(Thereafter) + 44 1980 557000

Justin Gover, Managing Director

GW PR: Financial Dynamics

+ 44 20 7831 3113

Ben Atwell / John Dineen

GW Nominated Adviser: Peel Hunt LLP

+44 (0)20 7418 8900

James Steel / Vijay Barathan

Sativex®

Sativex® was developed by UK-based GW Pharmaceuticals plc in specific response to the MS population’s unmet need for a prescription cannabis-based medicine. Manufactured under Home Office licence at an undisclosed location in the UK it is marketed in Europe (except the UK) by Almirall.

Sativex® is indicated as add-on treatment for symptom improvement in patients with moderate to severe spasticity due to multiple sclerosis (MS) who have not responded adequately to other anti-spasticity medication and who demonstrate clinically significant improvement in spasticity related symptoms during an initial trial of therapy. Sativex® is delivered by an oromucosal spray (sprayed into the mouth either onto the inside of the cheek or under the tongue) and has a flexible dosing regime, particularly appropriate given the variable nature of both spasticity and multiple sclerosis from patient to patient.

Sativex® Regulatory Status

Sativex® was approved in the UK and Spain in 2010. In March 2011, GW announced the successful completion of its first European Mutual Recognition Procedure (MRP) with all six countries involved recommending approval – Germany, Italy, Denmark, Sweden, Austria and the Czech Republic. A further MRP is planned for later 2011 in order to expand the approval to other European countries.

GW Pharmaceuticals

GW Pharmaceuticals plc (AIM:GWP) was founded in 1998 and is listed on the AiM, a market of the London Stock Exchange. Operating under licence from the UK Home Office, the company researches and develops cannabinoid pharmaceutical products for patients who suffer from a range of serious ailments, in particular MS and cancer pain. GW has assembled a large in-house scientific team with expertise in cannabinoid science as well as experience in the development of both plant based prescription pharmaceutical products and medicines containing controlled substances. GW occupies a world leading position in cannabinoids and has developed an extensive international network of the most prominent scientists in the field.

For further information, please visit www.gwpharm.com

This news release may contain forward-looking statements that reflect GWs current expectations regarding future events, including development and regulatory clearance of the GW’s products. Forward-looking statements involve risks and uncertainties. Actual events could differ materially from those projected herein and depend on a number of factors, including (inter alia), the success of the GW’s research strategies, the applicability of the discoveries made therein, the successful and timely completion of uncertainties related to the regulatory process, and the acceptance of Sativex® and other products by consumer and medical professionals.